From aaa99c35bdcde8bec9d44ca23814f323a4e09c75 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Mon, 19 Sep 2016 01:30:07 +0200
Subject: [PATCH] Added $past, $stable, $rose, $fell SVA functions
---
frontends/ast/genrtlil.cc | 10 +++
frontends/ast/simplify.cc | 133 +++++++++++++++++++++++++++++++++++++-
2 files changed, 141 insertions(+), 2 deletions(-)
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index d00738ecd..3c57162aa 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -765,6 +765,16 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
}
break;
}
+ if (str == "\\$past") {
+ if (GetSize(children) > 0) {
+ sub_width_hint = 0;
+ sub_sign_hint = true;
+ children.at(0)->detectSignWidthWorker(sub_width_hint, sub_sign_hint);
+ width_hint = max(width_hint, sub_width_hint);
+ sign_hint = false;
+ }
+ break;
+ }
/* fall through */
// everything should have been handled above -> print error if not.
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 8387c11c6..57aa648ce 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -63,7 +63,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
#if 0
log("-------------\n");
- log("AST simplify[%d] depth %d at %s:%d,\n", stage, recursion_counter, filename.c_str(), linenum);
+ log("AST simplify[%d] depth %d at %s:%d on %s %p:\n", stage, recursion_counter, filename.c_str(), linenum, type2str(type).c_str(), this);
log("const_fold=%d, at_zero=%d, in_lvalue=%d, stage=%d, width_hint=%d, sign_hint=%d, in_param=%d\n",
int(const_fold), int(at_zero), int(in_lvalue), int(stage), int(width_hint), int(sign_hint), int(in_param));
// dumpAst(NULL, "> ");
@@ -522,6 +522,11 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
children_are_self_determined = true;
break;
+ case AST_FCALL:
+ case AST_TCALL:
+ children_are_self_determined = true;
+ break;
+
default:
width_hint = -1;
sign_hint = false;
@@ -537,6 +542,9 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
detectSignWidth(width_hint, sign_hint);
}
+ if (type == AST_FCALL && str == "\\$past")
+ detectSignWidth(width_hint, sign_hint);
+
if (type == AST_TERNARY) {
int width_hint_left, width_hint_right;
bool sign_hint_left, sign_hint_right;
@@ -1682,9 +1690,128 @@ skip_dynamic_range_lvalue_expansion:;
goto apply_newNode;
}
+ if (str == "\\$past")
+ {
+ if (width_hint <= 0)
+ goto replace_fcall_later;
+
+ int num_steps = 1;
+
+ if (GetSize(children) != 1 && GetSize(children) != 2)
+ log_error("System function %s got %d arguments, expected 1 or 2 at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+
+ if (!current_always_clocked)
+ log_error("System function %s is only allowed in clocked blocks at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+
+ if (GetSize(children) == 2)
+ {
+ AstNode *buf = children[1]->clone();
+ while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+ if (buf->type != AST_CONSTANT)
+ log_error("Failed to evaluate system function `%s' with non-constant value at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
+
+ num_steps = buf->asInt(true);
+ delete buf;
+ }
+
+ AstNode *block = nullptr;
+
+ for (auto child : current_always->children)
+ if (child->type == AST_BLOCK)
+ block = child;
+
+ log_assert(block != nullptr);
+
+ int myidx = autoidx++;
+ AstNode *outreg = nullptr;
+
+ for (int i = 0; i < num_steps; i++)
+ {
+ AstNode *reg = new AstNode(AST_WIRE, new AstNode(AST_RANGE,
+ mkconst_int(width_hint-1, true), mkconst_int(0, true)));
+
+ reg->str = stringf("$past$%s:%d$%d$%d", filename.c_str(), linenum, myidx, i);
+ reg->is_reg = true;
+
+ current_ast_mod->children.push_back(reg);
+
+ while (reg->simplify(true, false, false, 1, -1, false, false)) { }
+
+ AstNode *regid = new AstNode(AST_IDENTIFIER);
+ regid->str = reg->str;
+ regid->id2ast = reg;
+
+ AstNode *rhs = nullptr;
+
+ if (outreg == nullptr) {
+ rhs = children.at(0)->clone();
+ } else {
+ rhs = new AstNode(AST_IDENTIFIER);
+ rhs->str = outreg->str;
+ rhs->id2ast = outreg;
+ }
+
+ block->children.push_back(new AstNode(AST_ASSIGN_LE, regid, rhs));
+ outreg = reg;
+ }
+
+ newNode = new AstNode(AST_IDENTIFIER);
+ newNode->str = outreg->str;
+ newNode->id2ast = outreg;
+ goto apply_newNode;
+ }
+
+ if (str == "\\$stable" || str == "\\$rose" || str == "\\$fell")
+ {
+ if (GetSize(children) != 1)
+ log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+
+ if (!current_always_clocked)
+ log_error("System function %s is only allowed in clocked blocks at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+
+ AstNode *present = children.at(0)->clone();
+ AstNode *past = clone();
+ past->str = "\\$past";
+
+ if (str == "\\$stable")
+ newNode = new AstNode(AST_EQ, past, present);
+
+ else if (str == "\\$rose")
+ newNode = new AstNode(AST_LOGIC_AND, new AstNode(AST_LOGIC_NOT, past), present);
+
+ else if (str == "\\$fell")
+ newNode = new AstNode(AST_LOGIC_AND, past, new AstNode(AST_LOGIC_NOT, present));
+
+ else
+ log_abort();
+
+ goto apply_newNode;
+ }
+
+ if (str == "\\$rose" || str == "\\$fell")
+ {
+ if (GetSize(children) != 1)
+ log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+
+ if (!current_always_clocked)
+ log_error("System function %s is only allowed in clocked blocks at %s:%d.\n",
+ RTLIL::unescape_id(str).c_str(), filename.c_str(), linenum);
+
+ newNode = new AstNode(AST_EQ, children.at(0)->clone(), clone());
+ newNode->children.at(1)->str = "\\$past";
+ goto apply_newNode;
+ }
+
// $anyconst is mapped in AstNode::genRTLIL()
- if (str == "\\$anyconst")
+ if (str == "\\$anyconst") {
+ recursion_counter--;
return false;
+ }
if (str == "\\$clog2")
{
@@ -2092,6 +2219,8 @@ skip_dynamic_range_lvalue_expansion:;
did_something = true;
}
+replace_fcall_later:;
+
// perform const folding when activated
if (const_fold)
{